The present invention relates to a method for the production of polyamide nanocomposites made from polyamides and phyllosilicates according to the preamble of claim 1. Polyamide nanocomposites produced according to the present method in accordance with the invention can be used for producing transparent packaging means, especially packaging means with high UV absorption, as well as improved gas and aroma barrier effect. Moreover, the polyamide nanocomposites produced in accordance with the invention further offer the possibility of producing moulded bodies, hollow bodies, semi-finished products, plates, tubes, etc., even such of larger thickness or wall thickness.
In the field of plastic, nanocomposites materials are understood as polymer formulations which comprise finely dispersed phyllosilicates such as clay minerals within the polymer matrix. The relevant aspect is that the phyllosilicates are exfoliated up to the individual layers, i.e. they are split up and then dispersed. The properties of such nanocomposites have already been published in numerous patent specifications and specialised publications. It is known that finely dispersed clay minerals or phyllosilicates provide the composite with improved properties such as increased mechanical strength, improved barrier properties against oxygen and carbon dioxide, among other things. The improvement of the properties of a polymer matrix by means of finely dispersed clay materials has already been described in closer detail in the patents U.S. Pat. Nos. 4,739,007 and 4,810,734 for example.
Nanocomposites have also already entered the packaging sector. The exfoliated clay minerals ensure in packaging films an inhibited diffusion of gas molecules such as oxygen, carbon dioxide or aromatics through the packaging material.